Japanese Language Stack Exchange is a question and answer site for students, teachers, and linguists wanting to discuss the finer points of the Japanese language. It only takes a minute to sign up.
Sign up to join this community
I know that の can be used instead of が when modifying a noun like in these examples:
But in these cases:
健康のためにあるいはリクリエーションのためにというスポーツのある一方で、スポーツが仕事というプロスポーツも存在している。
頂点に通じる長い山道のどこを歩いているのかの違いであり、険しさや空気の薄さは上に行くほどつらくはなるが、歩いて進むことや歩き方には変わりはない。
Why is の used here in the parts in bold？ Isn't it supposed to be が? I get the meaning but don't understand the grammar here.
As you say の can replace が as a subject marker.
For the first sentence, just as in 1 and 2 in the question, の/が are (to an extent) interchangeable: スポーツのある/スポーツがある are both fine.
In the second one, using が is most probably possible and won't change meaning much. But grammatically, as noted in the comment, they are different:
The sentence as is has an implicit subject which should be what is being discussed: (それは)...どこを歩いているのかの違いであり, which literally means It is a matter of where you are walking....
On the other hand, using が would make where you... the subject (of である）: どこを歩いているかが違いである = Where you are walking ... is the difference. This is ok grammatically, but it sounds like emphasizing the difference and does not seem to fit the context (the emphasis should be 変わりはない).
